Prenatal glucocorticoid treatment, used to speed up the development of a preterm infant's lungs, has the potential to worsen the outcome of later exposures to toxins, according to findings by the Duke University Superfund Research Program (SRP). The study in rats, led by Ed Levin, Ph.D., and Ted Slotkin, Ph.D., explored how exposure to glucocorticoids, a type of steroid, before birth changes the effect of the insecticide chlorpyrifos on behavioral development.